Taiwania 60(3): 117‒122, 2015 DOI: 10.6165/tai.2015.60.117

Argyreia akoensis (), a new species from southern Taiwan

Sheng-Zehn Yang, (1*) Po-Hao Chen(1) and George W. Staples(2)

1. Department of Forestry, National Pingtung University of Science and Technology, 1 Shuefu Rd., Neipu, Pingtung 91201, Taiwan. 2. HRA, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, U.K *Corresponding author: [email protected]

(Manuscript received 24 April 2015; accepted 26 June 2015)

ABSTRACT: A new species, Argyreia akoensis S.-Z. Yang, P.-H. Chen & Staples (Convolvulaceae) from southern Taiwan, is described and illustrated. Compared to its congeners in Taiwan and neighboring areas, Argyreia akoensis can be differentiated by the corolla lobing, sepal size, and exserted pistil and stamens. A morphological description, diagnosis, line drawings, photographs, and conservation status, as well as a key to similar species are provided to aid in identification.

KEY WORDS: Argyreia formosana, biogeography, endemism, Liangshan, Pingtung, Taiwan.

INTRODUCTION

The Argyreia Loureiro is the most taxonomically complex and difficult of the Asian genera of Convolvulaceae and no revision or monograph for the whole genus exists (Traiperm and Staples, 2014). The number of species reported varies from 90 species (Ooststroom and Hoogland, 1953, Mabberley, 2008) to 125 species (Staples and Brummitt, 2007) and was recently increased to 135 species (Traiperm and Staples, 2014). For Taiwan, Staples and Yang (1998) treated one endemic species, A. formosana Ishigaki ex T. Yamazaki, with a second species, A. nervosa (Burm. f.) Bojer introduced and cultivated only. In 2014, one unknown Argyreia species was collected

in southern Taiwan; while morphologically similar to A. formosana (Fig. 1) in vegetative characters the corolla Fig.1. Argyreia formosana. A: Habit, leaves ovate-cordate. morphology and color are quite different from that B: Inflorescence, about 4–6 flowered, peduncle distinctly species. shorter than the petiole. C: Corolla funnel-form, deeply We have compared this unknown with several 5-lobed, all white in color; pistil and stamens obviously exserted. species already described that could possibly be conspecific with it (Table 1), and consulted floras for leaves subcordate at base; corolla tube 3 cm long; East Asia and Malesia (Ooststroom and Hoogland, staminal filaments inserted at the mouth of the corolla 1953), particularly the Philippines. None of the tube; ovary bilocular; and short peduncles. previously described species matches this unknown Type: TAIWAN: Pingtung County: Machia Taiwan plant and we conclude that there is no specific Township, Liangshan, elev. 150–200 m; 30 October name available for it; it is here described as a new 2014, P.-H. Chen 499 (holotype K!; isotypes A!, PPI!). species, Argyreia akoensis. Liana, stems dextrorsely twining, up to 8 cm diam., younger parts sparsely appressed-pilose. Leaves TAXONOMIC TREATMENT alternate, ovate, 5.5–17.5 × 4–12.5 cm, upper surface sparsely appressed-pilose, lower surface densely Argyreia akoensis S.-Z. Yang, P.-H. Chen & G.W. appressed-pilose, apex acute, base subcordate, margin Staples, sp. nov. 屏東朝顏 Figs. 2–5 entire, venation reticulate, nerves 8–14 on either side of Similar to Argyreia sumbawana Ooststr. (in midrib; petioles 2.5–8.5 cm long, sparsely Ooststroom and Hoogland, 1953: 499) in having a appressed-pilose. Inflorescence cymose, 1–6-flowered; shallowly 5-lobed corolla, pistil much longer than peduncles 2–5 cm long, distinctly shorter than the corolla, but differing from that species by petioles; pedicels 4–6 mm long, appressed-pilose; obovate-oblong bracts, 5–7 mm long, 2–5 mm wide; bracts obovate-oblong, 5–7 × 2–5 mm, outside brown 117

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Table 1. Morphological comparison of Argyreia akoensis with five similar species

Argyreia Argyreia Ipomoea Argyreia Argyreia Characters Argyreia mollis akoensis formosana harmandii nervosa sumbawana LEAF

Leaf size (cm) 5.5–17.5 × 4–12.5 6–11 × 5–9 5–10 × 6–9 4–15 × 1.5–7 10–30 × 8–25 6–13 × 3–8.5 kidney or elliptic to narrowly Leaf shape ovate ovate- cordate suborbicular oblong ovate to orbicular ovate slightly emarginate to Leaf base subcordate cordate or deeply cordate acute or attenuate deeply cordate truncate or shortly subtruncate attenuate sparsely densely to sparsely Leaf upper sparsely glabrous sericeous, appressed-hairy or glabrous or nearly densely surface appressed-pilose glabrescent glabrous so appressed-sericeous Lateral nerves 8–14 7–10 4–5 9–18 11–16 9–14

FLOWER Petiole length (cm) 2.5–8.5 1.5–6 6–10 1–6 <10 2.5–6 Peduncle length (cm) 2–5 1.5–2 0.7 0.5–2.5 >20 3–11 ovate to oblong or Bracts shape obovate- oblong oblong - obovate- oblong elliptic ovate- lanceolate Bract length (mm) 5–7 6–4 - - 35–50 - Sepal length (mm) 6–9 5–8 10–20 8–10 >15, 10–12 5–6.5 Corolla length (cm) 3.6 1.8–2.0 - 5-6.5 6 2.5 Corolla 5-lobed shallowly deeply deeply shallowly shallowly shallowly Pistil & stamens included or exserted exserted included included included exserted exserted Number of ovary locules 2 2 2 4 4 4 FRUIT

Fruit color unknown red unknown red or orange red yellowish brown unknown

and densely appressed-pilose, inside brown and humidity. Vines twine around Dimocarpus longan Lour. glabrous, soon caducous. Flowers pendant; sepals 5, and Flueggea virosa (Willd.) Voigt. and its associated imbricate, orbicular or oblong, outside green and species included Albizia procera (Roxb.) Benth., densely appressed-pilose, inside green and glabrous, Bauhinia championii (Benth.) Benth, Broussonetia outer 2 orbicular, 7–9 × 7–9 mm, inner 3 oblong, 6–7 × papyrifera (L.) Vent., Callicarpa formosana Rolfe var. 5–6 mm; corolla broadly campanulate, outside glabrata Chen & Yang, Kleinhovia hospita L., white-pink, inside center purple-red, the midpetaline Lepidagathis formosensis Hayata and Mallotus bands sericeous, for the rest glabrous, corolla tube repandus (Willd.) Muell.-Arg. about 3 cm long, limb about 4 cm diam., ruffled; Distribution: known so far from three populations stamens 5, exserted, filaments filiform, 13–15 mm long, distributed in the Liangshan area, Pingtung County, glabrous, inserted at the mouth of the tube, dilated and Taiwan. densely pilose at the base, with septate hairs; anthers Elevation: 150–200 m. dorsifixed, pink, 2–3 mm long; pistil exserted, style 1, Conservation assessment: There is not yet enough about 2.7 cm long; stigma capitate, 2-lobed, about 2 information about the distribution, abundance, nor mm long; disc annular, margin entire; ovary globose, threats to this species; we consider it Data Deficient glabrous, about 2 mm long, 2-loculed, 4-ovuled. Fruits (DD) at this time. immature, seeds not seen. Additional specimen examined: TAIWAN: Pingtung Phenology: Flowering in October to November. County: Liangshan, 26 October 2014, P.-H. Chen 498 (TAI). The were discovered in vegetative condition on 24 May 2014; the first flowers were observed on 30 Discussion October. During subsequent visits (22 Nov., 20 Dec., 2014 and 25 Jan., 2015) the leaves were yellowing, In our efforts to identify this Taiwan Argyreia we flowering had ended, but the ovaries were not maturing compared it with species from nearby geographical into fruits. We continued to visit the plants but still areas including China, Vietnam, and the Philippines, as haven’t found the fruit stage. Further observations are well as using the keys for identification in the Flora of needed to record details of the fruits and seeds. China (Fang and Staples, 1995) and the Flora Ecology: Three populations grow along the trail Malesiana accounts for Convolvulaceae (Ooststrooom sides on a mountain slope in the forested area, on a and Hoogland, 1953). Among the several species we gravel substrate, exposed to full sun and lower compared the Taiwan plants with are: A. mollis (Burm. 118 September 2015 Yang et al.: Argyreia akoensis, a new species from southern Taiwan

Fig. 2. Argyreia akoensis. A: Habit, the population growing at hillside. B: Inflorescence cyme, about 1–6 flowered, peduncle distinctly shorter than the petiole. C: Corolla funnel-formed, shallowly 5-lobed, abaxial white-pink in color, adaxial center purple-red in color. D: Leaves, adaxially sparsely appressed-pilose, abaxially densely appressed-pilose. E: Pistil much longer than corolla, stigma capitate, 2-lobed; stamens 5, nearly as long as corolla; anther dorsifixed, pink. F: Petiole 2.5–8.5 cm long.

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Fig. 3. Argyreia akoensis S.-Z. Yang, P.-H. Chen & G. W.Staples. A. flowering branch; B. flower; C. bracts (abaxial view); D. bracts (adaxial view); E. sepals (abaxial view), outermost (left) to innermost (right); F. sepals (adaxial view), outermost (left) to innermost (right); G. dissected corolla (abaxial view); H. dissected corolla (adaxial view) and stamens; I. stamen; J. pistil; K. calyx and ovary (cross-sectional view); L. portion of leaf (adaxial view); M. portion of leaf (abaxial view). Drawn by Dr. Chun-kuei Liao from P.-H. Chen 499 (holotype!).

120 September 2015 Yang et al.: Argyreia akoensis, a new species from southern Taiwan

Fig. 5. Argyreia akoensis. A: Dissected calyx with densely appressed-pilose indumentum (abaxial view), innermost sepal (left) to outermost (right). B: Adaxial calyx green and glabrous, inner sepals 3, oblong (left), outer 2, orbicular (right). C: Bracts 4, soon caducous, abaxially brown in color Fig. 4. Argyreia akoensis. A: Dissected corolla, adaxial view, and densely appressed-pilose. D: Adaxial bracts brown in purple-red in color. B: Dissected corolla, abaxial, with five midpetaline bands. C: Ovary 2-loculed, 4-ovuled. D: Stamens color and glabrous. Scale: A–D: 5 mm. equal in length, dilated at the base with pilose hairs; pistil with ring-like disc at the base, yellow in color. Scale: A, B, D: ACKNOWLEDGEMENTS 1 cm; C: 1 mm. We heartily thank Dr. Chun-Kuei Liao, working in f.) Choisy from Hainan and Hong Kong; Ipomoea National Sun Yat-Sen University, for preparing the line harmandii Gagnep. from Vietnam; and several species drawings of Argyreia akoensis. Dr Chang-Fu Hsieh (TAI) of Argyreia from Malesia. The Malesian species most provided critical assistance with localizing old place names similar to the Taiwan plants is A. sumbawana Ooststr., and locating type specimens. We also thank the English editor from the island of Sumbawa in Indonesia. The and two anonymous reviewers for kindly improving our differences between A. akoensis and these similar manuscript. species from nearby areas are summarized in Table 1 and the key to six similar Argyreia species is provided LITERATURE CITED as an aid to identification. Fang, R. Z. and G. W. Staples. 1995. Convolvulaceae. In: 1a. Pistil and stamens exserted from corolla; sepals less than 9 mm Wu, C. Y. and Raven, P. H. (eds.), Flora of China 16, pp. long…………………………………………………….…...... ….2 271–327. 1b. Pistil and stamens included; sepals longer than 10 mm…………. Mabberley, D. J. 2008. Mabberley’s Plant – Book. ……………………..…………………..……….….……………....4 Cambridge University, UK, 1021 pp. 2a. Corolla deeply lobed, white………...... Argyreia formosana Ooststroom, S. J. van and R. D. Hoogland. 1953. 2b. Corolla shallowly lobed, pinkish……………..…………………. 3 3a. Corolla ca 3.6 cm long; ovary 2- loculed ….….Argyreia akoensis Convolvulaceae. In: Steenis, C. G. G. J. van (ed.), Flora 3b. Corolla ca 2.5 cm long; ovary 4- loculed…..Argyreia sumbawana Malesiana, ser. I, 4, pp. 388–512. 4a. Corolla deeply lobed; ovary 2-loculed…...... Ipomoea harmandii Staples, G. W. and R. K. Brummitt. 2007. Convolvulaceae. 4b. Corolla shallowly lobed, ovary 4-loculed …….….…….……...... 5 In: Heywood, V. H. et al. (eds.) Families 5a. Peduncle 0.5–2.5 cm long; bracts small, caducous; fruit red …… of the World. Firefly Editions, Buffalo NY, pp. 424. ……………………………….…………………..Argyreia mollis Staples, G. W. and S.-Z. Yang. 1998. Convolvulaceae. In: 5b. Peduncle longer than 20 cm; bracts large, persistent; fruit brown... Huang, T.-C. et al. (eds), Flora of Taiwan, ser. II, 4, pp. ……………………….……………….……….… 341–384. Traiperm, P. and G. W. Staples. 2014. A new endemic Thai species of Argyreia (Convolvulaceae). Phytotaxa 164: 281–285. Yamazaki, T. 1969. Argyreia in Formosa. J. Jap. Bot. 44: 160.

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台灣南部旋花科的新種-屏東朝顏

楊勝任(1＊) ；陳柏豪(1) ；George W. Staples(2)

1.國立屏東科技大學森林系，912 屏東縣內埔鄉學府路1 號，91201，臺灣。 2. HRA, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, U.K. * 通信作者。Tel: 886-8-7703202 ext. 7408; Email: [email protected]

(收稿日期：2015 年 4 月 24 日；接受日期：2015 年 6 月 26 日)

摘要：本文將台灣南部旋花科新種-屏東朝顏(Argyreia akoensis S.-Z. Yang, P.-H. Chen & G.W. Staples)，與台灣及鄰近地區相似種進行比較，屏東朝顏鑑別特徵為花冠裂片、花萼大 小、突出的雌蕊和雄蕊。本文提供形態描述、判別特徵、手繪圖、照片、保育狀況以及相 似種的檢索表以供鑑別之用。

關鍵詞：鈍葉朝顏、生物地理學、固有性、涼山、屏東。

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